The present invention relates to methods for producing chewing gum. More particularly the invention relates to producing chewing gum containing a high amount of stimulant known as caffeine. The caffeine that is added to the chewing gum has been treated to control its rate of release in chewing gum.
In recent years, efforts have been devoted to controlling release characteristics of various ingredients in chewing gum. Most notably, attempts have been made to delay the release of sweeteners and flavors in various chewing gum formulations to thereby lengthen the satisfactory chewing time of the gum. Delaying the release of sweeteners and flavors can also avoid an undesirable overpowering burst of sweetness or flavor during the initial chewing period. On the other hand, some ingredients have been treated so as to increase their rate of release in chewing gum.
Besides sweeteners, other ingredients may require a controlled release from chewing gum. Stimulants such as caffeine may be added to gum; however, stimulants are not generally released very readily. Caffeine may be encapsulated in a water soluble matrix such that, during the chewing period, the caffeine may be released quickly resulting in a fast release of stimulant as in a beverage. This would allow chewing gum to be a carrier for caffeine and, with its fast release, to be an effective stimulant.
On the other hand, serious taste problems may arise because of the bitter nature of caffeine. Thus, a prolonged or delayed release of caffeine would allow for the use of caffeine in gum, but the low level of release may keep the level below its taste threshold and not give chewing gum a bitter taste quality. Also, slow release may allow some individuals to more easily tolerate caffeine and not cause gastrointestinal distress.
Thus, there are specific advantages to adding caffeine to chewing gum by controlled release mechanisms.
Caffeine use in chewing gum was disclosed in U.S. Pat. No. 1,298,670.
Chewing gum containing caffeine as a stimulant and to combat fatigue and migraine headaches is disclosed in French Patent No. 2,345,938 and in West Germany Patent No. 4,342,568.
Also, two Japanese Patent Publications, Nos. JP 91-112450 and JP 91-251533, disclose use of caffeine in chewing gum to reduce drowsiness.
In Japanese Patent Publication No. JP 96-019370, caffeine is added to chewing gum as an after-meal chewing gum to replace tooth brushing.
Caffeine is a well known stimulant from coffee and tea, and several patents disclose use of coffee or tea in gum, such as Japanese Patent Publication No. JP 94-303911, South Korea Patent Publication No. 94-002868, and PCT Patent Publication No. WO 95-000038.
The present invention is a method of producing chewing gum with physically modified caffeine to control its release. The present invention also relates to the chewing gum so produced. Caffeine may be added to sucrose type gum formulations, replacing a small quantity of sucrose. The formulation may be a low or high moisture formulation containing low or high amounts of moisture containing syrup. Caffeine may also be used in low or non-sugar gum formulations, replacing a small quantity of sorbitol, mannitol, other polyols or carbohydrates. Non-sugar formulations may include low or high moisture sugar free chewing gums.
Caffeine may be combined or codried with bulk sweeteners typically used in chewing gum, such as sucrose, dextrose, fructose and maltodextrins, as well as sugar alcohols such as sorbitol, mannitol, xylitol, maltitol, lactitol, hydrogenated isomaltulose and hydrogenated starch hydrolyzates.
The modified release rate noted above may be a fast release or a delayed release. The modified release of caffeine is obtained by encapsulation, partial encapsulation or partial coating, entrapment or absorption with high or low water soluble materials or water insoluble materials. The procedures for modifying the caffeine include spray drying, spray chilling, fluid bed coating, coacervation, extrusion and other agglomerating and standard encapsulating techniques. Caffeine may also be absorbed onto an inert or water-insoluble material. Caffeine may be modified in a multiple step process comprising any of the processes, or a combination of the processes noted. Prior to encapsulation, caffeine may also be combined with bulk sweeteners including sucrose, dextrose, fructose, maltodextrin or other bulk sweeteners, as well as sugar alcohols such as sorbitol, mannitol, xylitol, maltitol, lactitol, hydrogenated isomaltulose and hydrogenated starch hydrolyzates.
Prior to encapsulation, caffeine may be combined with high-intensity sweeteners, including but not limited to thaumatin, aspartame, alitame, acesulfame K, saccharin acid and its salts, glycyrrhizin, cyclamate and its salts, stevioside and dihydrochalcones. Co-encapsulation of caffeine along with a high-intensity sweetener may reduce the bitterness of caffeine and control the sweetener release with caffeine. This can improve the quality of the gum product and increase consumer acceptability.
In addition to use of high-intensity sweeteners, bitterness inhibitors such as sodium gluconate, sodium ascorbate or other sodium salts may be combined with caffeine prior to encapsulation to reduce the overall bitterness caused by caffeine and result in a gum product having increased consumer acceptability.
Caffeine is a natural chemical found in a variety of food products such as coffee, tea, cocoa, chocolate, and various other beverages. Caffeine is known as an effective stimulant to increase energy and reduce drowsiness. Caffeine has a naturally bitter taste. The bitterness, however, actually improves the flavor perception of some beverages such as coffee and carbonated beverages.
When caffeine is added to chewing gum at a level of about 0.2% to about 5%, caffeine imparts an intense bitterness to the chewing gum that lasts throughout the chewing period. The higher the level used, the stronger the bitterness. At about 0.2%, which is about 5 mg per 2.7 gram stick, the bitterness is below the threshold limit and is not readily discernible. Taste limits in chewing gum are generally about 0.4% (10 mg) to about 4% (100 mg) of caffeine in a stick of gum. The 60-80 mg level of caffeine is about the level of caffeine found in a conventional cup of coffee. The target level of caffeine in stick gum is about 40 mg per stick, with a range of about 25-60 mg, so that a five stick package of gum would contain about 200 mg of caffeine, or the equivalent of caffeine in two strong cups of coffee. However, at this level caffeine bitterness overwhelms the flavor initially and lasts throughout the chewing period.
With the caffeine release modified to result in a fast release of caffeine with the chewing gum solubles and sweeteners, the bitterness can be effectively reduced. If high-intensity sweeteners can be blended with caffeine to release at the same time, this too can reduce the bitterness effect. Other chemicals that inhibit bitterness may be blended with caffeine to also reduce bitterness.
Caffeine is not a highly water soluble substance and, therefore, has a moderately slow release from chewing gum. Caffeine is 2.1% soluble in water at room temperature, 15% soluble in water at 80xc2x0 C. and 40% soluble in boiling water. This gives caffeine a moderately slow release as shown below:
Generally, highly water soluble ingredients are about 80-90% released after only five minutes of chewing. For caffeine, only about 50% is released, while the other 50% remains in the gum after five minutes of chewing. After 20 minutes almost 90% of caffeine is released.
Even if caffeine is dissolved in hot water and mixed in the gum, when the gum is cooled or kept at room temperature, caffeine may return to its normal crystalline state and release at the same rate as shown above.
Caffeine salt compounds such as caffeine citrate, caffeine sodium benzoate, caffeine sodium salicylate, which may be more water soluble and less bitter than caffeine, may also be encapsulated or entrapped for controlled release in accordance with the present invention.
Caffeine can be added to chewing gum as a powder, as an aqueous dispersion, or dispersed in glycerin, propylene glycol, corn syrup, hydrogenated starch hydrolyzate, or any other compatible aqueous dispersion.
For aqueous dispersions, an emulsifier can also be mixed in the solution with the caffeine and the mixture added to a chewing gum. A flavor can also be added to the caffeine/emulsifier mixture. The emulsion formed can be added to chewing gum. Powdered caffeine may also be mixed into a molten chewing gum base during base manufacture or prior to manufacture of the gum. Caffeine may also be mixed with base ingredients during base manufacture.
As stated previously, caffeine releases slowly from chewing gum during the early stages of mastication of the gum because of its low solubility in water. Physical modifications of the caffeine by encapsulation with a highly water soluble substrate will increase its release in chewing gum by increasing the solubility or dissolution rate of caffeine. Any standard technique which gives partial or full encapsulation of the caffeine can be used. These techniques include, but are not limited to, spray drying, spray chilling, fluid-bed coating and coacervation. These encapsulation techniques may be used individually in a single step process or in any combination in a multiple step process. The preferred technique for fast release of caffeine is spray drying.
Caffeine may also be encapsulated or entrapped to give a delayed release from chewing gum. A slow, even release of caffeine can give a reduced bitterness over a long period of time and blend more easily with longer lasting flavors and sweeteners. Caffeine may be encapsulated with sweeteners, specifically high-intensity sweeteners such as thaumatin, dihydrochalcones, acesulfame K, aspartame, sucralose, alitame, saccharin and cyclamates. These can also have the effect of reducing bitterness. Additional bitterness inhibitors can also be combined with caffeine and sweeteners to give a reduced bitterness with delayed release caffeine.
The encapsulation techniques described herein are standard coating techniques and generally give varying degrees of coating from partial to full coating, depending on the coating composition used in the process. Generally, compositions that have high organic solubility, good film-forming properties and low water solubility give better delayed release of caffeine, while compositions that have high water solubility give better fast release. Such low water-solubility compositions include acrylic polymers and copolymers, carboxyvinyl polymer, polyamides, polystyrene, polyvinyl acetate, polyvinyl acetate phthalate, polyvinylpyrrolidone and waxes. Although all of these materials are possible for encapsulation of caffeine, only food-grade materials should be considered. Two standard food-grade coating materials that are good film formers but not water soluble are shellac and Zein. Others which are more water soluble, but good film formers, are materials like agar, alginates, a wide range of cellulose derivatives like ethyl cellulose, methyl cellulose, sodium hydroxymethyl cellulose, and hydroxypropylmethyl cellulose, dextrin, gelatin, and modified starches. These ingredients, which are generally approved for food use, may give a fast release when used as an encapsulant for caffeine. Other encapsulants like acacia or maltodextrin can also encapsulate caffeine and give a fast release rate of caffeine in gum.
The amount of coating or encapsulating material on the caffeine may also control the length of time for its release from chewing gum. Generally, the higher the level of coating and the lower the amount of active caffeine, the slower the release during mastication with low water soluble compositions. The release rate is generally not instantaneous, but gradual over an extended period of time. To obtain the delayed release to blend with a gum""s flavor release, the encapsulant should be a minimum of about 20% of the coated caffeine. Preferably, the encapsulant should be a minimum of about 30% of the coated caffeine, and most preferably should be a minimum of about 40% of the coated caffeine. Depending on the coating material, a higher or lower amount of coating material may be needed to give the desired release.
Another method of giving a modified release of caffeine is agglomeration with an agglomerating agent which partially coats the caffeine. This method includes the step of mixing caffeine and an agglomerating agent with a small amount of water or other solvent. The mixture is prepared in such a way as to have individual wet particles in contact with each other so that a partial coating can be applied. After the water or other solvent is removed, the mixture is ground and used as a powdered, coated caffeine.
Materials that can be used as the agglomerating agent are the same as those used in encapsulation mentioned previously. However, since the coating is only a partial encapsulation and caffeine is not very water soluble, some agglomerating agents are more effective in increasing the caffeine""s release than others. Some of the better agglomerating agents for delayed release are the organic polymers like acrylic polymers and copolymers, polyvinyl acetate, polyvinylpyrrolidone, waxes, shellac and Zein. Other agglomerating agents are not as effective in giving a delayed release as are the polymers, waxes, shellac and Zein, but can be used to give some delayed release. Other agglomerating agents that give a fast release include, but are not limited to, agar, alginates, a wide range of water soluble cellulose derivatives like ethyl cellulose, methyl cellulose, sodium hydroxymethyl cellulose, hydroxypropylmethyl cellulose, dextrin, gelatin, modified starches, and vegetable gums like guar gum, locust bean gum and carrageenan. Even though the agglomerated caffeine is only partially coated, when the quantity of coating is increased compared to the quantity of caffeine, the release of caffeine can also be modified for mastication. The level of coating used in the agglomerated product is a minimum of about 5%. Preferably, the coating level is a minimum of about 15% and more preferably about 20%. Depending on the agglomerating agent, a higher or lower amount of agent may be needed to give the desired release of the caffeine.
Caffeine may be coated in a two-step process or a multiple step process. Caffeine may be encapsulated with any of the materials as described previously and then the encapsulated caffeine can be agglomerated as previously described to obtain an encapsulated/agglomerated/caffeine product that could be used in chewing gum to give a delayed release of the caffeine.
In another embodiment of this invention, caffeine may be absorbed onto another component which is porous and become entrapped in the matrix of the porous component. Common materials used for absorbing caffeine include, but are not limited to, silicas, silicates, pharmasorb clay, spongelike beads or microbeads, amorphous carbonates and hydroxides, including aluminum and calcium lakes, all of which result in a delayed release of caffeine. Other water soluble materials including amorphous sugars such as spray-dried dextrose, sucrose, alditols and vegetable gums and other spray-dried materials result in a faster release of caffeine.
Depending on the type of absorbent materials and how it is prepared, the amount of caffeine that can be loaded onto the absorbent will vary. Generally materials like polymers or spongelike beads or microbeads, amorphous sugars and alditols and amorphous carbonates and hydroxides absorb about 10% to about 40% of the weight of the absorbent. Other materials like silicas and pharmasorb clays may be able to absorb about 20% to about 80% of the weight of the absorbent.
The general procedure for absorbing caffeine onto the absorbent is as follows. An absorbent like fumed silica powder can be mixed in a powder blender and an aqueous solution of caffeine can be sprayed onto the powder as mixing continues. The aqueous solution can be about 1 to 2% solids, and higher solid levels to 15-30% may be used if temperatures up to 90xc2x0 C. are used. Generally water is the solvent, but other solvents like alcohol could also be used if approved for use in food. As the powder mixes, the liquid is sprayed onto the powder. Spraying is stopped before the mix becomes damp. The still free-flowing powder is removed from the mixer and dried to remove the water or other solvent, and is then ground to a specific particle size.
After the caffeine is absorbed or fixed onto an absorbent, the fixative/caffeine can be coated by encapsulation. Either full or partial encapsulation may be used, depending on the coating composition used in the process. Full encapsulation may be obtained by coating with a polymer as in spray drying, spray chilling, fluid-bed coating, coacervation, or any other standard technique. A partial encapsulation or coating can be obtained by agglomeration of the fixative caffeine mixture using any of the materials discussed above.
Another form of encapsulation is by entrapment of an ingredient by fiber extrusion or fiber spinning into a polymer. Polymers that can be used for extrusion are PVAC, hydroxypropyl cellulose, polyethylene and other types of plastic polymers. A process of encapsulation by fiber extrusion is disclosed in U.S. Pat. No. 4,978,537, which is hereby incorporated by reference. The water insoluble polymer may be preblended with caffeine prior to fiber extrusion, or may be added after the polymer is melted. As the extrudate is extruded, it results in small fibers that are cooled and ground. This type of encapsulation/entrapment generally gives a very long, delayed release of an active ingredient.
The four primary methods to obtain a modified release of caffeine are: (1) encapsulation by spray drying, fluid-bed coating, spray chilling and coacervation to give full or partial encapsulation, (2) agglomeration to give partial encapsulation, (3) fixation or absorption which also gives partial encapsulation, and (4) entrapment into an extruded compound. These four methods, combined in any usable manner which physically isolates caffeine and modifies its dissolvability or modifies the release of caffeine, are included in this invention.
A method of isolating caffeine from other chewing gum ingredients is to add caffeine to the dusting compound of a chewing gum. A rolling or dusting compound may be applied to the surface of chewing gum as it is formed. This rolling or dusting compound serves to reduce sticking of the chewing gum product to machinery as it is formed and as it is wrapped, and sticking of the product to its wrapper after it is wrapped and is being stored. The rolling compound comprises caffeine powder in combination with mannitol, sorbitol, sucrose, starch, calcium carbonate, talc, other orally acceptable substances or a combination thereof. The rolling compound constitutes from about 0.25% to about 10%, but preferably about 1% to about 3% by weight of the chewing gum composition. The amount of caffeine powder added to the rolling compound is about 0.05% to about 20% of the rolling compound or about 5 ppm to about 2000 ppm of the chewing gum composition. This method of using caffeine powder in the chewing gum allows for a lower usage level of caffeine, gives the caffeine a fast release rate, reduces caffeine bitterness when used with sweeteners and reduces or eliminates any possible reaction of the caffeine with gum base, flavor components, or other components, yielding improved shelf stability.
Another method of isolating caffeine is to use it in the coating/panning of a pellet chewing gum. Pellet or ball gum is prepared as conventional chewing gum, but formed into pellets that are pillow shaped or into balls. The pellets/balls can then be sugar coated or panned by conventional panning techniques to make a unique sugar coated pellet gum. Caffeine is very stable but not highly water soluble and can be easily dispersed in a sugar solution prepared for sugar panning. Caffeine can also be added as a powder blended with other powders often used in some types of conventional panning procedures. Using caffeine in a coating isolates it from other gum ingredients and modifies its release rate in chewing gum. Levels of caffeine may be about 100 ppm (0.01%) to about 25,000 ppm (2.5%) in the coating and about 50 ppm (0.005%) to about 10,000 ppm (1%) of the weight of the chewing gum product. The weight of the coating may be about 20% to about 50% of the weight of the finished gum product.
Conventional panning procedures generally coat with sucrose, but recent advances in panning have allowed the use of other carbohydrate materials to be used in the place of sucrose. Some of these components include, but are not limited to, dextrose, maltose, palatinose, xylitol, lactitol, hydrogenated isomaltulose and other new alditols or a combination thereof. These materials may be blended with panning modifiers including, but not limited to, gum arabic, maltodextrins, corn syrup, gelatin, cellulose type materials like carboxymethyl cellulose or hydroxymethyl cellulose, starch and modified starches, vegetable gums like alginates, locust bean gum, guar gum, and gum tragacanth, insoluble carbonates like calcium carbonate or magnesium carbonate and talc. Antitack agents may also be added as panning modifiers which allow for the use of a variety of carbohydrates and sugar alcohols in the development of new panned or coated gum products. Flavors may also be added with the sugar coating and with caffeine to yield unique product characteristics.
Another type of pan coating would also isolate caffeine from the chewing gum ingredients. This technique is referred to as film coating and is more common in pharmaceuticals than in chewing gum, but procedures are similar. A film like shellac, Zein, or cellulose-type material is applied onto a pellet-type product forming a thin film on the surface of the product. The film is applied by mixing the polymer, a plasticizer and a solvent (pigments are optional) and spraying the mixture onto the pellet surface. This is done in conventional type panning equipment, or in more advanced side-vented coating pans. When a solvent like alcohol is used, extra precautions are needed to prevent fires and explosions, and specialized equipment must be used.
Some film polymers can use water as the solvent in film coating. Recent advances in polymer research and in film coating technology eliminates the problem associated with the use of flammable solvents in coating. These advances make it possible to apply aqueous films to a pellet or chewing gum product. Although caffeine is not highly water soluble, it may be added to this aqueous film solution and applied with the film to the pellet or chewing gum product. The aqueous film, or even the alcohol solvent film, in which caffeine is dispersed may also contain a flavor along with the polymer and plasticizer.
The previously described encapsulated, agglomerated or absorbed caffeine may readily be incorporated into a chewing gum composition. The remainder of the chewing gum ingredients are noncritical to the present invention. That is, the coated particles of caffeine can be incorporated into conventional chewing gum formulations in a conventional manner. Coated caffeine may be used in a sugar chewing gum or a sugarless chewing gum. The coated caffeine may be used in either regular chewing gum or bubble gum.
In general, a chewing gum composition typically comprises a water-soluble bulk portion, a water-insoluble chewable gum base portion and typically water-insoluble flavoring agents. The water-soluble portion dissipates with a portion of the flavoring agent over a period of time during chewing. The gum base portion is retained in the mouth throughout the chew.
The insoluble gum base generally comprises elastomers, resins, fats and oils, waxes, softeners and inorganic fillers. Elastomers may include polyisobutylene, isobutylene-isoprene copolymer and styrene butadiene rubber, as well as natural latexes such as chicle. Resins include polyvinylacetate and terpene resins. Fats and oils may also be included in the gum base, including tallow, hydrogenated and partially hydrogenated vegetable oils, and cocoa butter. Commonly employed waxes include paraffin, microcrystalline and natural waxes such as beeswax and carnauba. According to the preferred embodiment of the present invention, the insoluble gum base constitutes between about 5% and about 95% by weight of the gum. More preferably the insoluble gum base comprises between about 10% and about 50% by weight of the gum, and most preferably between about 20% and about 35% by weight of the gum.
The gum base typically also includes a filler component. The filler component may be calcium carbonate, magnesium carbonate, talc, dicalcium phosphate or the like. The filler may constitute between about 5% and about 60% by weight of the gum base. Preferably, the filler comprises about 5% to about 50% by weight of the gum base.
Gum bases typically also contain softeners, including glycerol monostearate and glycerol triacetate. Further, gum bases may also contain optional ingredients such as antioxidants, colors, and emulsifiers. The present invention contemplates employing any commercially acceptable gum base.
The water-soluble portion of the chewing gum may further comprise softeners, sweeteners, flavoring agents and combinations thereof. Softeners are added to the chewing gum in order to optimize the chewability and mouth feel of the gum. Softeners, also known in the art as plasticizers or plasticizing agents, generally constitute between about 0.5% and about 15% by weight of the chewing gum. Softeners contemplated by the present invention include glycerin, lecithin and combinations thereof. Further, aqueous sweetener solutions such as those containing sorbitol, hydrogenated starch hydrolyzates, corn syrup and combinations thereof may be used as softeners and binding agents in gum.
As mentioned above, the coated caffeine of the present invention may be used in sugar or sugarless gum formulations. Sugar sweeteners generally include saccharide-containing components commonly known in the chewing gum art which comprise, but are not limited to, sucrose, dextrose, maltose, dextrin, dried invert sugar, fructose, levulose, galactose, corn syrup solids and the like, alone or in any combination. Sugarless sweeteners include components with sweetening characteristics but which are devoid of the commonly known sugars and comprise, but are not limited to, sugar alcohols such as sorbitol, mannitol, xylitol, hydrogenated starch hydrolyzates, maltitol and the like, alone or in any combination.
Depending on the particular caffeine release profile and shelf-stability needed, the coated caffeine of the present invention can also be used in combination with uncoated high-potency sweeteners or with high-potency sweeteners coated with other materials and by other techniques.
A flavoring agent may also be present in the chewing gum in an amount within the range of from about 0.1% to about 10%, preferably from about 0.5% to about 3%, by weight of the gum. The flavoring agents may comprise essential oils, synthetic flavors, or mixtures thereof including, but not limited to oils derived from plants and fruits such as citrus oils, fruit essences, peppermint oil, spearmint oil, clove oil, oil of wintergreen, anise, and the like. Artificial flavoring components are also contemplated for use in gums of the present invention. Those skilled in the art will recognize that natural and artificial flavoring agents may be combined in any sensorally acceptable blend. All such flavors and flavor blends are contemplated by the present invention.
Optional ingredients such as colors, emulsifiers and pharmaceutical agents may be added to the chewing gum.
In general, chewing gum is manufactured by sequentially adding the various chewing gum ingredients to a commercially available mixer known in the art. After the ingredients have been thoroughly mixed, the gum mass is discharged from the mixer and shaped into the desired form such as by rolling into sheets and cutting into sticks, extruding into chunks or casting into pellets.
Generally, the ingredients are mixed by first melting the gum base and adding it to the running mixer. The base may also be melted in the mixer itself. Color or emulsifiers may also be added at this time. A softener such as glycerin may also be added at this time, along with syrup and a portion of the bulking agent. Further portions of the bulking agent may then be added to the mixer. A flavoring agent is typically added with the final portion of the bulking agent. The coated caffeine of the present invention is preferably added after the final portion of bulking agent and flavor have been added.
The entire mixing procedure typically takes from five to fifteen minutes, but longer mixing times may sometimes be required. Those skilled in the art will recognize that many variations of the above described procedure may be followed.